Python: Keyerror:0 when doing a loop

I am trying to follow the code to extract keyphrases from a pandas column. Link to the jupyter notebook

Whenever I try to run I always get an error in the line with the regex operation.

corpus = []dataset['word_count'] = dataset[datacol].apply(lambda x: len(str(x).split(" ")))ds_count = len(dataset.word_count)for i in range(0, ds_count):    # Remove punctuation    text = re.sub('[^a-zA-Z]', '', str(dataset[datacol][i])) # the error is here

This is the error I am getting. Does anyone know what could have possibly caused this?

---> 58     text = re.sub('[^a-zA-Z]', '', pr_df['Comment'][i])File C:\Program Files\Anaconda3\Lib\site-packages\pandas\core\series.py:981, in Series.__getitem__(self, key)    978     return self._values[key]    980 elif key_is_scalar:--> 981     return self._get_value(key)    983 if is_hashable(key):    984     # Otherwise index.get_value will raise InvalidIndexError    985     try:    986         # For labels that don't resolve as scalars like tuples and frozensetsFile C:\Program Files\Anaconda3\Lib\site-packages\pandas\core\series.py:1089, in Series._get_value(self, label, takeable)   1086     return self._values[label]   1088 # Similar to Index.get_value, but we do not fall back to positional-> 1089 loc = self.index.get_loc(label)   1090 return self.index._get_values_for_loc(self, loc, label)File C:\Program Files\Anaconda3\Lib\site-packages\pandas\core\indexes\base.py:3804, in Index.get_loc(self, key, method, tolerance)   3802     return self._engine.get_loc(casted_key)   3803 except KeyError as err:-> 3804     raise KeyError(key) from err   3805 except TypeError:   3806     # If we have a listlike key, _check_indexing_error will raise   3807     #  InvalidIndexError. Otherwise we fall through and re-raise   3808     #  the TypeError.   3809     self._check_indexing_error(key)KeyError: 0